A mechanical seal which is an example of a slide component is evaluated for its performance by a leakage rate, a wear rate, and a torque. In the conventional arts, by optimizing the seal material and the sliding face roughness of mechanical seals, their performance is increased to achieve low leakage, long life, and low torque. However, due to growing awareness of environmental problems in recent years, a further improvement in the performance of mechanical seals has been demanded, for which technology development beyond the limits of the conventional arts has been required.
In that context, for example, as those used for oil seal devices for rotating components such as turbochargers, those including a rotating shaft rotatably received in a housing, a disk-shaped rotor rotating together with the rotating shaft, and a stationary body fixed to the housing and abutting an end face of the rotor for preventing an oil from leaking from the outer peripheral side to the inner peripheral side, in which an annular groove which generates positive pressure by a centrifugal force of fluid is provided in the abutting surface of the stationary body so as to prevent the oil from leaking from the outer peripheral side to the inner peripheral side are known (see Patent Document 1, for example).
Moreover, for example, in shaft seal devices of the rotating shaft which seal toxic fluid, those including a rotating ring, and a stationary ring mounted to a casing, together with the rotating shaft, in which a spiral groove which entrains a liquid on a low-pressure side toward a high-pressure side by the rotation of the rotating ring is provided in the sealing face of either the rotating ring or the stationary ring such that an end on the high-pressure side is formed in a dead-end shape so as to prevent a sealed fluid on the high-pressure side from leaking to the low-pressure side are known (see Patent Document 2, for example).
Moreover, for example, as face seal structures suitable for sealing a drive shaft of the turbocharger with respect to a compressor housing, those in which, of a pair of cooperating seal rings, one is provided as a rotating component and the other is provided as a stationary component, these seal rings have seal surfaces formed substantially radially, a seal gap for sealing zones provided outward of the seal surfaces against zones provided inward of the seal surfaces in operation is formed between the seal surfaces, a plurality of recesses effective for feeding gas and circumferentially spaced from one another are provided in at least one of the seal surfaces, the recesses are extended from one peripheral edge toward the other peripheral edge of the seal surface and inner ends of the recesses are provided to be radially spaced from the other peripheral edge of the seal surface, and thus a non-gas component in a gas medium containing the non-gas component is sealed are known (see Patent Document 3, for example).